The peak in alcohol use prevalence during young adulthood is especially pronounced among college students (IOM and NRC, 2015). Heavy episodic drinking (HED; 4+/5+ drinks on a single occasion for women/men) and extreme drinking (8+/10+ drinks) are of particular concern given the heightened risk of negative consequences, including sexual assault, injury, and motor vehicle accidents. College students are at heightened risk for excessive use and consequences (Grekin & Sher, 2006; Hoeppner et al., 2013; Johnston et al., 2014; White et al., 2006). The theory of planned behavior has been applied to college student alcohol use, including HED (Ajzen, 1991). A key component of Ajzen's theory of planned behavior is the ability of intentions to predict later behavior. However, individuals may consume more alcohol than intended; in particular, HED and extreme drinking may be either planned or unplanned. Unintended heavy drinking, specifically drinking more heavily than intended and reaching blood alcohol concentrations higher than anticipated, may contribute to the elevated risk of consequences since students may be less likely to plan ahead to use protective behavioral strategies (PBS), such as designating a driver. College students' PBS use has been associated with less alcohol use and fewer negative consequences in cross-sectional research. However, only three longitudinal studies have examined links between PBS and negative consequences for specific drinking occasions; furthermore, in contrast to cross-sectional research, these studies have found that use of serious harm reduction PBS was linked to more alcohol use and consequences. The proposed study will provide a critical contribution by improving our understanding of occasion-specific associations among unintended heavy drinking, PBS, and consequences among college students. This study will recruit college students aged 18-24 who engaged in HED in the last month. Across a total of eight weeks, students will complete morning and afternoon web surveys to obtain daily reports for 24 weekend days (Thursday, Friday, Saturday) and 4 random weekdays. We will evaluate: (1) daily links between unintended heavy drinking and negative consequences and PBS use as a mediator, (2) daily links between heavy drinking intentions and consequences and PBS plans as a mediator, and (3) daily links between intentions and behavior for drinking and PBS and explore potential moderators of these associations (e.g., future time perspective). The proposed study is significant and innovative in that (a) it will be the first to examine unintended heavy an extreme drinking in relation to PBS and negative consequences in a prospective, longitudinal design evaluating occasion-specific drinking, and (b) provide direct tests of intention-behavior links to test the theory of planned using daily reports. The findings of the proposed study will identify the role of behavior- and intention-based predictors of consequences and can identify specific etiological paths to target in individual-level brief interventions and real-time interventions.